I need to encrypt a string using a public key (.pem file), and then sign it using a private key (also a .pem).
I am loading the .pem files fine:
publicCert = fs.readFileSync(publicCertFile).toString();
But after hours of scouring Google, I can't seem to find a way to encrypt data using the public key. In PHP I simply call openssl_public_encrypt(), but I don't see any corresponding function in Node.js or in any modules.
A library is not necessary. Enter crypto.
Here's a janky little module you could use to encrypt/decrypt strings with RSA keys:
var crypto = require("crypto");
var path = require("path");
var fs = require("fs");
var encryptStringWithRsaPublicKey = function(toEncrypt, relativeOrAbsolutePathToPublicKey) {
var absolutePath = path.resolve(relativeOrAbsolutePathToPublicKey);
var publicKey = fs.readFileSync(absolutePath, "utf8");
var buffer = Buffer.from(toEncrypt);
var encrypted = crypto.publicEncrypt(publicKey, buffer);
return encrypted.toString("base64");
};
var decryptStringWithRsaPrivateKey = function(toDecrypt, relativeOrAbsolutePathtoPrivateKey) {
var absolutePath = path.resolve(relativeOrAbsolutePathtoPrivateKey);
var privateKey = fs.readFileSync(absolutePath, "utf8");
var buffer = Buffer.from(toDecrypt, "base64");
var decrypted = crypto.privateDecrypt(privateKey, buffer);
return decrypted.toString("utf8");
};
module.exports = {
encryptStringWithRsaPublicKey: encryptStringWithRsaPublicKey,
decryptStringWithRsaPrivateKey: decryptStringWithRsaPrivateKey
}
I would recommend not using synchronous fs methods where possible, and you could use promises to make this better, but for simple use cases this is the approach that I have seen work and would take.